Nonlinear H∞ control applied to biped robots

In this paper, a control strategy based on nonlinear H∞ approach is applied in a biped robot with torso, knees, and feet, that presents a passive dynamic walking. To obtain an anthropomorphic gait, the Foot Rotation Indicator was used as control variable. The H∞ control adopted is based on the Linear Parameter Varying (LPV) approach with a quasi-LPV representation of the biped robot. Results obtained from simulation show that the proposed controller increases the basin of attraction of the system limit cycle against external disturbances.